BBC Verify has been analysing footage from the Belgorod region that emerged on social media on Monday.

So far, the team has located a video apparently filmed from a drone that features several armoured vehicles near a border checkpoint south of Belgorod. Additionally, BBC Verify has geolocated footage of helicopters operating in the region.

The footage is recent, but it is hard to say for certain from the videos what the exact sequence of events is.